Du Ponceau wrote to his sister for 65 years after his departure to America, and his brother attempted to write to him later on, though it is unknown if he was able to reach him.

[3][4] Du Ponceau served as a secretary, translator, and interpreter to the Baron von Steuben in the Continental Army during the American Revolution.

Among his acquaintances were many important figures of the American Revolution, including Alexander Hamilton, John Laurens, Lafayette and James Monroe.

[7] Du Ponceau also worked on Asian languages and was one of the first Western linguists to reject the axiomatic classification of Chinese writing as ideographic.

[8] Du Ponceau stated: He used the example of Vietnamese, then called "Cochinchinese," which used Chữ Nôm, a modified form of Chinese characters.